Hi ,have just bought a Savex L39 fitted with a wren 44 gold ,does anyone know what control throws work best ,also best c of g, as mine seems abit twitchy regards jon

John,
C of G is 85 90 mm back of LE.
You'll get everything you need here:
http://www.rcuniverse.com/forum/m_1396336/tm.htm
First fly with the throws advised in the manual is fine, then fine tune to suit your liking.

Page 14 of the thread (use the link from Yanns post) details the throws used by Paul Gray. I have copied the throws below but i would recommend reading the thread as there is a lot of info about this model.

I have had a lot of PM asking for movement settings for the model.
Mine are below, plane flys really well like this.

CG is set 80mm back from Leading edge at the route with tanks empty.

elevator = 10mm each way measured at route.
Rudder = Nose wheel and rudder are on a Y lead so i set rudder to 15mm each way to give correct steering on the ground. I link Rates for Rudder to Retract switch so once gear is up movement increases to 20 mm each way measured at the bottom of rudder. The plane will knife edge on this.

Ailerons = 5mm up and 5mm down measured at tip.

Flaps take off = about 10 degree (no elevator mix)
Flaps for landing = all you can get and mix in a very slight amount of Down elevator (1-2mm) this stops the plane 'zooming'

These settings are good for me and they should be safe for 1st flights, you will adjust to suit when you have flown.

Paul

Hi,

besides the data, kwb gave you i strongly recommend to measure and maybe correct the angle between wing and elevator. Mine was 3.5 degrees when delivered and i reduced it to 1 degree for better flight performance. Maybe it was only my machine (and it flew with 3.5 degree!) but its worth having a look on this.

Best regards
Hajo

3.5 degree ??? that seems to be a lot !!!
How did you reduce it, did you change the hole for the centering peg in the front of each elevator halves ?

Hello, Yann,

you exactly described the way I did it. At first I was hesitant whether the angle of the elevator to the ground will prolong start distance on grass but nothing negative happened. Make sure you exactly fix the angle before glueing it again.

I reduced the angle in two steps, first to 1.5 degrees. The model flew better but still climbed a lot at full throttle. In the second step I reduced it to 1 degree (maybe a little less) and I am now satisfied. I guess people who like to pull on the elevator all the time while flying might find it comfortable to reduce the angle to 0.5 degrees.

Best regards
Hajo

Are you sure the climb on full power is not due to incorrect thrust line?

I never noticed this on my L39. It is also true that it is a hair trimmed down. Nothing like few degrees anyway.

Have to say that i have had no problem with all 3 of mine![8D]

Thats why I mentioned it[sm=thumbs_up.gif]

Hi guys,

as I told you this occurred with my one. I never read before from somebody with the same experience. Savex says that the angle should be in between 1 - 1.5 degrees, mine definitely was 3.5 but it flew ;-)
I checked thrustline as well and it was ok.

Finally: I dont want to discourage anybody from buying this jet, the opposite is true. I love to fly it but dont love the weather which is preventing me from doing it ;-)

Best regards
Hajo

Good info here. Mine should arrive in a couple weeks!

Carl

You really need to read the original L39 thread started by Paul Gray

http://www.rcuniverse.com/forum/m_13..._1/key_/tm.htm

There is also another thread on www.rcmf.co.uk

You will need to join to look at the jet stuff and then the link is below

http://www.rcmf.co.uk/4um/index.php?topic=29593.0

Most of this info by Lozza is also on the Paul Gray thread but you will need to find it (I find the search function very poor). This thread is a lot smaller and has some good info and ideas.

I am building my model at the moment and will post all the pics and info at the end of the build. I thought it was better this way for other L39 builders as I have found the info I need on these two threads but it is sometimes hard to locate.

kwb, I have checked out the 145 page turbine thread and have been sifting through. That is too much. I'll pick up the good info I can. Perhaps I'd better join the uk forum and get info from a shorter thread. I too prefer a build thread posted in full after building. It keeps the entire build in 2 or 3 pages and all the questions and discussion afterwards. I hope you will post the thread link here when you are ready.

thanks,
Carl

The other thread is definately worth a look. I have read the big thread several times and still struggle to find info I know is in there somewhere!

I have mine w/ 301 spring air retracts. Wanted to fit some struts on but found the 301s stock wire gear will lay right against the air cylinder. How do you fit a wider strut over a wire that is already up against the cylinder? There's no room.